PL110411B1 - Method and apparatus for regulating tube pressure welding tamperatures in rolling mills during resistance welding when employing high-frequency currents - Google Patents

Description

The subject of the invention is a method and device for regulating the welding temperature in a tube rolling mill with high-frequency resistance welding, in particular a method and device for controlling the welding by measuring the parameters of the welding process and using the measurement results as input values of the control system values. in order to regulate the welding temperature. In the known resistance welding process, in the manufacture of steel pipes, high frequency currents, for example 450 kHz, are introduced by sliding contact electrodes into a web on a tube which has already been formed into a shape. non-welded pipe in order to heat the edge to the welding temperature. At a short distance from these electrodes, the sealing pressure rollers apply pressure to the edges of the heated strip to form a final welded tube. At such current frequencies as are conventionally used, the current flows primarily through the edges of the strip, and as a result of heat dissipation on the resistance, the edge temperature rises to the welding temperature as the strip continuously moves under the electrodes to the rollers. Resistance welding mills are usually not provided with fusion temperature or welding current and voltage indicators. There are measuring devices used to indicate the DC current and the anode voltage at the operating points of the generator electron tubes, which produce a high frequency heating current, but these measuring devices are only useful for determining the initial conditions and are weak. ¬ not a concept of the current welding conditions. The operator of the rolling mill regulates the anodic tension or the rolling speed in order to obtain the correct heating of the welding area. This heating is determined by visual observation of the edge of the strip or the color of the weld seam of the material rolled by the rolling rolls during the welding process, or both. US Pat. No. 3,548,141 describes the method of welding edges. Today, a metal strip with a curved welding seam, in which the edges move with respect to each other, with at least one of the edges following a substantially rectilinear path until the edges are closely adjacent to each other at a specific point. so that the front surfaces of the edges are opposite each other and the corresponding points on these front surfaces are about the same level. The edges then move, causing the edges to move along "curved cross tracks with respect to the direction of travel after reaching specified item 110 411lid 411 here and while maintaining such mutual relationship of the edges, but reducing the distance between the frontal surfaces of the edges, and the two in pfmkcfS? 4gtiewa * i3 hastepnym with respect to this defined point./ A current is delivered big ^^ c ^ sjp ^ i iwo; The edge of the edge at the travels iMip & tUi from r ^ ewaAia and between the fusion point "t is essentially said defined point, so that current flows along the edges when caused to move along curved tracks to heat the curved edges to the fusion temperature when reached. The device for welding an edge of a metal strip with a curved weld seam, known from this United States Patent No. 3,548,141, includes means for moving the edges relative to each other and for moving them. At least one edge along a substantially rectilinear path until the edges adjoining each other at a predetermined point meet each other so that the frontal surfaces of the edges are opposite each other and the corresponding points on these frontal surfaces are at the same level. The known device contains means for bending the edges into a bush to be fed as they move over a certain point, and to maintain such an edge relationship, but reducing the distance between them, until these edges are joined to each other at the fusion point next to that specific point. A high frequency current source is used to provide a welding current tto the edge as the welding point is moved and between the welding point and a substantially said specific point, thereby causing the current to flow along both edges into a curved form as the welding point and the gels are moved. There is also known from US Pat. No. 35T3 413 a method of regulating the welding in the production of longitudinally welded metal tubes from a metal band, which rests thereon. that the basic quantities are continuously measured - tape feeding speed, active electric welding power, pressure and temperature of the welding seam. One of these fundamental quantities is taken as a reference quantity, the measured values are converted into electrical signals, and the ratio of the signals corresponding to each three fundamental quantities is formed into a signal corresponding to the reference quantity to obtain the quadrature-ratio signals. three limit signals are introduced for these ratios so that they give optimal welding results. Each of the quotient signals is compared with a specific, predetermined limit signal to obtain three differential signals. An algebraic sum of the differential signals is produced to obtain a summation signal, causing this sum signal to affect at least one of the three basic quantities, up to the reduction of the differential signals. Known from this US Patent No. 3 573416 the device for regulating the welding in the manufacture of longitudinally welded metal tubes from a metal strip comprises four measuring devices, each of which serves for the continuous electrical measurement of the basic quantities - tape feed rate, active electrical welding power, pressure and seam temperature welding. The balance also includes three divisors, each of which receives the output signal of one of the measuring devices as an input signal. The output of the fourth measuring instrument is obtained as input to all dividers simultaneously. The device comprises three comparators, each of which is connected to one of the divisors and all connected in series are connected to the adder. The input signal of each comparator is formed by the output signal of the coupled divider and by the limit signal manually input to each comparator. The control circuit receives the sum signal from the adder and is adapted to act on the supply circuit of one of the basic quantities until the output signals of the comparators are reduced. Attempts to diffuse the temperature of the fusion point simply by using radiation pyrometers have completely failed due to the formation of water vapor, oil fumes, and changes in emissivity at the top of the seam. More importantly, only the tops of the edge of the heated tape can be inspected through the pyrimeters of radiation, and this does not provide accurate temperature readings over the entire tape surface. As the high frequency current at sharp edges is usually greater than on flat surfaces, the edges of the edges are The tapes are hotter than the leading edge surfaces of the tape. If the observation field of the radiation pyrometer covers part of the web edge, it is possible to measure the temperature of the end face of the web edge part, but the aforementioned difficulties negatively affect the accuracy obtained. In addition, this technique does not allow for the indication of the temperature value of the weld ridge, which shifts under the influence of dynamic welding conditions and which causes temperature changes according to dynamic changes in its line length. As long as an appropriate combination of the amount of heat supplied to the welding line and the crushing pressure is necessary to maintain a good portion of the shot, it is desirable to clearly adjust the welding temperature. Correct welding ensures not only the mechanical properties but also the quality of the weld, that is, the absence of various discontinuities that may arise with this welding technique. Proper adjustment of the heating and pressure force can significantly reduce: the occurrence of discontinuities in the weld and facilitates the adjustment of the material flow line in the fusion area. Research and experiments carried out on the resistance welding process of the pipes have revealed that the mass of steel per unit time in the area of heating, if all other factors, such as rolling speed, input power and wall thickness are kept constant, it determines the amount of heat applied to the steel and thus the temperature of the steel at the welding point. The mass of the material per unit time on the welding line is directly proportional to the volume heating the web between the high frequency energy supply electrodes in order to heat to the crest of the weld line or to a rolling point located between the final rolling rolls where the weld line is formed. For a sufficiently constant power supplied from the high frequency generator for heating, the penetration depth of the high frequency current in the pipe material is substantially constant for the type of material within the limits of acceptable chemical variation, so that the volume that is heated is proportional. to the wall thickness and the length of the welding line or heating area. For a nominally constant wall thickness, the length of the welding line or heating area is the factor determining the heat dissipation and the temperature of the welding point. The dynamic length of the welding line, if all other factors remain constant, determines the temperature at the welding point and vice versa. , may be a function of the fusion point temperature. Variations in the sealing pressure as well as certain conditions for forming the tube also change the length of the sealing line and thus the final sealing temperature. According to the invention, the method of regulating the sealing temperature consists in selecting a control factor whose value is the whist is compared with the value required for regulation, from the equation AT =? where • WS AT is the temperature increase of the welded material, Kr is the constant, I is the heating current, W is the wall thickness of the pipe i. S is the speed of the rolling mill. The rolling mill control parameters I and S 55 are continuously measured and a signal representing the thickness of the wall is continuously provided. Also, the single value of the control factor is continuously calculated based on the equation, knowing the measured value I, signal wall thickness and the value of the remaining factor in the equation. In a continuous manner, a differential signal is provided by comparing this one control factor value with another control factor value. Chooses; one of the control parameters of the rolling mill, and the control parameter of the rolling mill continuously changes depending on the differential signal. In one embodiment, the control factor is S, and the remaining control factor is i its value is used by the required value of KB and the control parameter of the rolling mill is S in the second embodiment as the control factor is KR AT, and as the remaining factor d its value is the actual value S and as the control parameter a rolling mill is used: In the method according to the invention, the static pressure exerted by the rolling rolls is measured, the dynamic pressure exerted by the rolling rolls is continuously measured, and the heating current is continuously calculated and adjusted to make a calculation from the measurements According to the invention, when changing the control parameter of the rolling mill, the differential signal is continuously converted into a signal oscillating, oscillating around zero, to change the control parameter of the cylinder, and "continuously limiting the value of the control signal, oscillating around zero, to a certain level above zero and to a specified level below zero. In the method of the invention, a signal is provided representing the required rolling pressure for calculating a specific value of the control factor; According to the invention, the value of the rolling pressure is controlled and the pressure is adjusted to a value within the required range, if the value is outside the required range. ¦ • The temperature control device according to the invention comprises a multiplier-divider for calculating the required speed of the rolling mill, ¦ = -; / KRi2 is based on the equation S =, where S is the rate of the rolling mill, I is the heating current, W is the wall thickness, Kr is the constant and AT is the required temperature rise of the welded material. The signal source is coupled to the calculator to supply it with a signal representing the actual wall thickness. The processing unit is connected to the counting system to supply it with a signal representing the actual heating current. A second signal source is coupled to the counting system to provide it with a signal representing VKR x AT. The components attached to the rolling mill provide a signal representing the actual speed of the rolling mill. The summation operational amplifier is connected to the counting circuit i110 411 f 8 to the signal supply means for comparing the actual speed of the rolling mill with the speed required of the rolling mill. The apparatus also includes components connected to the summation operational amplifier and the motor driving the rolling mill, sensitive to comparisons of the mentioned signals to change the speed of the driving motor of the rolling mill. high frequency power supply for welding power. The current sensor is placed in a groove on the surface of the set of conductive guides and has a ceramic core on which is wound a winding made of a thin insulating wire, surrounded by a protective glass tube. A core and a converter are attached to the winding to provide a current signal consistent with the counting system. According to the invention, the means for varying the speed of the motor driving the rolling mill include elements limiting the change in speed to a specific value below and a certain value above. fixed speed rolling mill in response aa. The apparatus according to the invention comprises pressure sensors for measuring the static pressure exerted by the rolling rolls, pressure sensors for measuring the dynamic pressure exerted by the rolling rolls, comparison elements attached to the pressure sensors for comparing static and dynamic stresses, and elements attached to comparing elements, to the circuit supplying the current signal and to the combiner, and the comparison sensitivity for supplying the regulated current signal to the computing circuit. In another embodiment, the apparatus according to the invention includes a multiplier-divider for computing the required value ———- according to the equality- TP¦? m =, where AT is the actual increment. the temperature of the welded material, Kr is constant, I is the heating current, W is the wall thickness, and S is the actual speed of the mill. The signal source is coupled to a multiplier to provide it with a signal * representing the actual wall thickness. The processing system is attached to the multiplier to provide a signal representing the actual heating current to it. The components attached to the multiplier and the rolling mill are used to provide a signal representing the actual speed of the rolling mill. to deliver 4? a signal representing - ^, where KR is a constant and .AT is the required temperature increase of the welded material. The summing operational amplifier and the sampling and memory circuit are connected to the multiplier-divider and to the components that provide the signal of the reporter- * AT seal —— for comparing the KR AT representative signal encompassing the real one with the Kr AT representative signal providing the required one. * The elements included in the comparison elements and the high-frequency power supply system are sensitive to the comparison of these signals for a change in the heating current. According to the invention, the processing system for supplying a signal representing - the actual heating current is provided with a transport unit running guides attached to a high frequency power source providing welding power. The current sensor is placed in a groove on the surface of the set of conductive guides and has a ceramic core on which is wound a winding made of a thin insulating wire, surrounded by a protective glass tube. The core and the converter are attached to the winding to provide a current signal according to the multiplier-divider. According to the invention, the means for changing the heating current include means to limit the change of the heating current to a certain value below and a certain value above a certain level of the heating current. pressure for measuring the static pressure exerted by the rolling rolls, pressure sensors for measuring the dynamic pressure exerted by the rolling rolls, and comparison elements attached to the static and dynamic pressure sensors. Elements attached to the comparison elements, the current signal supply and the calculating system are sensitive for a comparison to supply an adjustable current signal to a calculator. According to the invention, the manipulation of the heat power equation is used to obtain control, while in known methods and devices, variables are influenced by take the ratio regardless of the heat output equation. In addition, it has experimentally discovered certain compounds that are used for the control scheme that differ significantly from the known guidelines. For example, the known pressure-speed ratio used may lead to an unstable system because a change in the ratio will result in a temperature correction in the wrong condition. Moreover, the applicant has found that the welding power under the conditions: welding current X welding voltage is insensitive and essentially not It depends on changes in the welding area, while the welding current * is sensitive to dynamic changes. '".-...-. ¦.,. ..'.-.' .. For the purposes of self-regulation - according to the invention / - * lt 15 25 30 40 45 fi * 36lit 411 * mathematically expressed equations were used using the classical dependence on the heat power needed to heat the mass of a given value: TP = X MC AT (1) where TP is the thermal power in watts, X - constant, M - mass of the material to be heated in kilograms per minute , C - the specific heat of the material, AT - the increase in the temperature of the material in ° C. The thermal power is defined by the high frequency current as TP = PR (2) where I is the high frequency heating current used in the welding process, R - re The resistance of the welding line. The resistance R can be considered as a combination of two resistances in parallel, namely the resistance along the weld line and the resistance around the pipe wall. The first resistance can be defined by the formula: | ¦ PTAL (3) Rv = V? 8 where Rv is resistance along the welding line, PT - resistivity at the required temperature , Alu - the incremental length of the welding line, W - the thickness of the pipe wall material, 8 - the depth of penetration of the current. The resistances around the pipe wall can be represented as Rw WAL (4) where Rw is the resistance around the pipe wall, q - resistivity, D - circuit By combining equations (3) and (4), assuming that for a fixed welding temperature and where ki is constant, and that AL * = k2Dd (6) where k2 is constant, then the parallel connected resistances can be written as : gD kik2 R = "" WAL ktkg + 1 (7) Combining equations (1), (2) and (7) assuming that: m = was (8) where S is the pipe speed, leads to the following relationship with three factors - D AT kikf + 1- W WS WAL i (Q, c, d) where f (g, c, o) is a function of the material type, depending on the resistivity, specific heat and depth of penetration of current in the pipe material * Second factor- 10 Mi kjkj + l 'equation (7 rapre-15 WAL presents the static conditions of the diameter to wall ratio and the length of the welding line, which are determined by as the dimensions of the rollers, shapes and holes to properly shape the pipe and are not changed in the process. The third factor, f (g, c, d), represents metallurgical and thermodynamic influences, representing background changes for which no dynamic measurements can be made. Therefore, only the first factor Ia / WS is an index used in regulation. It has been found that the first factor P / WS is an indicator of changes in the dynamic length of the welding line that occur during welding, because if the length of the welding line increases, the value of the heating high frequency current decreases, which it reduces the welding temperature and if the length of the welding line decreases, the current and temperature increase. For a fixed length of the welding line, the welding current decreases and increases in order to decrease and increase the welding temperature. Thus, the factor IVWS has been determined in order to determine those changes which change the fusion temperature when all parameters related thereto are covered by the second and third factor of equation (9) by being proportional to the resistance Constant Kr. There are cases where the hardness of the material along the pipe, and hence the resistivity, will vary according to the considerations considered when adjusting the welding. These changes can be determined by measuring the forces used in the pressure sealing rollers, which is a partial recognition of the third factor of equation (9). Changes in the static forces have been measured and found to have little effect on the final weld temperature, except for large variations that affect the length of the weld line. Dynamic changes in the level of forces during the production cycle show changes in hardness and arising problems with the influence of both these factors on temperature. welding. Thus, the ratio of dynamic to static force levels can be used to show the mechanical and material changes that cause changes in the welding temperature. Therefore, equation (9) can be rewritten as 9 'AT = KrP / WS + KAAF / F) (10) where Kr is a constant proportional to the resistance, KF - constant proportional to the silite, Af '- the level of dynamic force, F - the level of static force. The value of the constant Kr must be determined experimentally, but a single the value corresponds to the wall thicknesses and diameters (0.005mm to 0.02mm and 0.25mm to 0.8mm) typically formed by a resistance welding process. For smaller diameters and thinner walls, the value of the constant KF must reflect the reduced sensitivity of the sealing temperature to the crushing force and the dynamic changes that directly reflect the sealing temperature. The constant KF is a proportion constant determined by the relationship AT and AFIF. According to the invention, the method and apparatus for regulating the welding temperature in the electric resistance welding process in the production of welded pipes are based on the measurement of the welding current. The regulation according to the invention may also be based on the measurement of the rolling speed. The subject of the invention is illustrated in the example of the drawing, in which Fig. 1 schematically shows the basic elements used in the production of pipes welded by the method of electric resistance welding. 2 - conductive guide assemblies used in the implementation of the method according to the invention, in perspective view, Fig. 3 - schematically, in a partial section, a sensor for determining the welding current, Fig. 4 - block diagram of the device for adjustment according to a first embodiment of the invention and Fig. 5 a block diagram of an adjustment device according to a second embodiment of the invention Fig. 1 shows a portion 2 of the length of a web on a tube which has already been formed in the tube 4 by movement in the direction of arrow 6 8 contact electrodes are connected to a 10 high frequency power source to supply a heating current and along with it. from the edge of the 12 welding lines and through the seam 14 of the weld. The rollers 16 close the webs onto the tubing to form the final form of a weld, starting at the top of the weld, and with the forming rollers (not shown) guide the material through the mill. Roll pressure sensors 20 indicate the rolling force exerted by the rollers 16. This is picture of a conventional electric resistance welding rolling mill. Fig. 2 shows two sets of conductive guides 22. The top of each guide is connected to a power source 10, and the lower end of each assembly includes a contact electrode 8. An inner surface 26 of one of the conductive assemblies 22 is provided on the inner surface of slot 24. In slot 24 is positioned the current sensor 28 of Fig. 3, the overall length of which is almost equal to that of bed 24. The current sensor 28 shown in Fig. 3 has an extrusion corundum core 30. Around a corundum core 30 are wrapped around there are about 10 turns of a thin insulating wire 32, consisting of five stranded copper wires, each insulated to minimize the eddy heating current in a strong magnetic field produced by a current of 450 kHz in the range of 400 to 600 amperes, which flows through the conductive guide: The core with the wound wire is placed inside the protective tube 34 made of glass and the ends 36 are connected to a processing circuit 38. The processing circuit 38 is a conventional circuit for converting a signal from the sensor to a signal compatible with other components of the control device described below. the sealing temperature control device comprises several conventional electronic circuits designed to perform the described functions. Roll pressure sensors 20 as shown in FIG. 1 provide a rolling force signal through switch 40 to sampling and memory system 42. The switch 40 and the output of circuit 42 are connected to the counting circuit 44, dividing, subtracting, and amplifying with control. The output of the processing unit 38 as shown in FIG. 3 and the output of the counting unit 44 are connected to the inputs of the summing op amp 50. The output 52 of the summing op amp 50 is connected to the first input of the counting circuit 54 of the multiplier-divider. A source 56 for wall thickness signal 58 is coupled to the second input of calculator 54. A source 60 for signal 62 representing K / IAT is coupled to the third input of link 54. 30 Calculator 54 provides output 64 representing the required rolling speed, fed to the first input of the operational amplifier 66. The summing operational amplifier 66 has an output 68 connected to the input of the regulator circuit 70 having a double-sided output. Regulator circuit 70 has an output connected to a deviation detector 74 which indicates the value and sign of signal 72 on the Output, and regulator circuit 70. An output is also connected to the input of limiter 76. Output of limiter 76 is connected to the first input summing op amp 80. A signal source 82 for the rolling speed signal 84 has an output connected to the second input of the summing op amp 80. The output 86 of summing op amp 80 is connected to a conventional control circuit 88 driving the rolling mill. which controls the speed of the file 90 driving the mill. The engine of the 90th is mechanically coupled to the tachymeter 92 to drive it. A tachymeter 92 provides an output 94 to the second input of the adder of op amp 66. The signal 94 is also fed to the first input of multiplier 96 which includes a digital voltmeter for displaying the number. "corresponding to AT. Circuit 96 in the multiplier-dividerA-; has: a second input 98 for supplying signals corresponding to KR, I2 and W from the counting circuit J4. During operation, switch 40 is moved to the right to connect sensors 20 to The pressure ratio of the rolls with sampling and memory system 4Z is cheap, while the rolling mill is at rest to obtain a statistical pressure F during rolling. When the rolling mill is operating, the switch 40 is moved to the left and the roll pressure sensors 20 generate then the dynamic rolling pressure AY The static level may be changed as the operation of the rolling mill varies with the type and size of the pipe. not calculator 44 is adjusted to provide an input constant KF which is experimentally determined. It is obvious that the constant KF described herein for providing a signal 48 may be a modification of the constant KF described in equation (10) based on the formula the arithmetic indicated in the figure for the computing circuit 44. The processing circuit 38 converts the output of the sensor 28, which is proportional to the fusion current, into a signal 46 consistent with other electronic signals of the assembly. Signal 48 compensates for variations in rolling pressure by modifying signal 46 to • provide signal 52, which is the signal used for I in counting system 54. Arrangement 56 may be a potentiometer providing a signal corresponding to the wall thickness, or more precisely, may be a signal of actual thickness. with a thickness gauge. The signal 62 is applied to the system 60, which may be a potentiometer, to reflect a constant KR which is experimentally determined and to reflect the desired sealing temperature at AT. The numerator 54 then calculates the required speed signal 64 as shown in the equation. This equation is not identical to equation (10), but it is% more convenient to use than the exact equation (10) and gives comparable results with fixed Kf and KR constant. Required, speed signal 64 and actual speed signal 94 are compared to provide differential signal 68 to control device 70. Control device 70 provides an output 72 which is negative when signal 52 decreases, indicating a decrease in sealing temperature and which is positive as signal 52 increases, indicative of increasing sealing temperature, causing an increase in the speed of the roller. The signal 72 is scaled in the limiter 76 to represent the required percentage of the primary speed signal 84, which is set by the mill operator such that the signal 78 drives above the restricted range of the primary signal for a predetermined practice under conditions where deviations occur. signal 52. The mill operator may at any time provide a new basic speed signal 84 * or change the limitations in the limiter 76 as required based on experience and practice for various types and sizes of pipe or as required to obtain the desired quality of welding. Limiter 76 may, for example, provide a plus or minus one hundredth the base speed, and if the deviation indicator 74 indicates a deviation outside this range, it is an indication to the operator that manual adjustment is required. A control signal 78 is combined with a speed signal 84 to provide a signal 86 for actual control of the speed of the rolling mill by the conventional speed control 83 of the mill. A tachymeter 92 connected to the mill motor provides the actual speed signal 94. The limiter 96 includes a digital voltmeter to display AT, which calculates as shown by I and W from the counting 54, S from the tachometric generator 92 and Kr from the internal potentiometer. In the event that there are little or no variation in the dynamic pressure during operation, it is not necessary to supply signal 48 and signal 46 directly to the computing circuit 54. However, in this case, however, it may become necessary to provide a fixed signal 48. and simply controlling the output of the roll pressure sensors 20 and changing the pressure when the control indicates that the pressure is not within the required range. The control system allows the operator to leave the station during normal operation at the welder and to track the ends of the weld by the machine. . The previously mentioned changes in the material, which were sometimes difficult to detect, are now easily identified. Changes in the weld that even the most experienced operator could not detect from the color of the weld can now be detected by the instruments and by the control system. The use of the control system resulted in an improvement in both the efficiency and the quality. The control system also eliminates automatically the problems associated with the welding current, caused by the bending of the tape, causing the formation of weld scales at the ends of the tape, respectively. Referring now to the device for regulating the welding temperature, given in Fig. 5, signals 52, 58 and 94 are the same signals as shown in the Fig. 4 embodiment and are provided in the same manner by the same circuits and are designated in the same manner as in Fig. 4. The multiplier-divider 100 has inputs for the signals 52, 58 and 94 and the output 102 represents the required fusion temperature expressed as -. The output 102 is diverted to the first input of the combiner 104 of the op-amp 104 and to the try-and-store circuit 100 via switch 108. Circuit 106 has an output 110 connected to the second input of summing circuit op amp 104, which has an output 68 connected to the input of control circuit 70. The control circuit 70 has an output connected to the input of the deviation indicator 74 and to the input of the limiter 76, the limiter 76 has an output connected to the first input of the amplifiers 15 20 25 30 35 45 50 55 60 110 411 15 II for control purposes, from equation AT 1WS 25 operating link 80. The elements already described, numbered 68 to 80, are the same as shown in Fig. 4. Signal source 112 has an output connected to the second the input of a summing amplifier Ot 5 operation 80, which has an output connected to the inputs of a conventional power control system 118 for a rolling mill with multiple resistance welding The device of FIG. 5 is similar to the embodiment of FIG. 4, but operation is performed at different parameters. After calculation, the multiplier 100 gives a signal 102 corresponding to the required temperature, which is compared with the required temperature by the probe and storage circuit 106, and a differential signal 68 is fed to the control circuit 70. The signal corresponding to the required temperature is temperature is applied to circuit 106 via closed switch 108 at the required level of signal 102. Control signal 78 is used to vary the current from the power supply through the limiter 76. In the apparatus of Fig. 4, the effect of rolling dynamic pressure may be eliminated. from the control system. Either speed (FIG. 4) or power (FIG. 5) can be a control parameter in the control system. Each of these solutions makes it possible to eliminate changes to a parameter not used for control such that the control system accurately reflects the changes in parameters during the process. The use of speed as a control parameter is advantageous in view of the maximum throughput of the rolling mill, and the use of the welding power for control has the advantage that no K overload occurs in the power supply, which reduces the possibility of damage to the components and increases the risk of damage to the components. Regulation range. Two embodiments of the invention have been described, but it is obvious that the control equation may be modified for other cases. Patent Claims 45 1. A method of regulating the welding temperature in a high frequency resistance welding pipe mill by the fact that in a continuous way, the basic values in welding are measured, characterized in that a control factor is selected, the actual value of which is compared with the required value, where AT is the temperature increase of the welded material, KR is constant, I is the heating current, W is the wall thickness of the tube and S is the speed of the rolling mill, continuously measuring parameters I and S for the control of the rolling mill continuously provide a signal representing the wall thickness i. continuously calculate one value of the control factor based on the equation, knowing the measured value of I, the signal of the thickness of the wall, and the value for the remaining factor in the equation, a differential signal is continuously provided by comparing this one control factor value with another control factor value, one of the rolling mill control parameters is selected and this roller control parameter is continuously varied according to the differential signal. 2. The method according to claim The method of claim 1, wherein S is used as the control factor and Kr is used as the remaining factor and its value. the required value of AT and S is used as the control parameter of the rolling mill. I, characterized in that AT is used as the control factor - the remaining factor and its value is used as the actual value of S, and I is used as the control parameter of the rolling mill. The method of claim 1, characterized in that the static pressure exerted by the rolling rolls is measured, the dynamic pressure exerted by the rolling rolls is continuously measured and the heating current is continuously calculated and the heating current is adjusted to make a calculation based on pressure measurements. static and dynamic. 5. The method according to p. The method of claim 1, characterized in that when the rolling mill control parameter is changed, the differential signal is continuously converted into a control signal, oscillating around zero, for the change of the rolling mill control parameter, and the value of the control signal, which oscillates around zero, is continuously limited to a specified value. to a level above zero and to a specific level below zero. 6. The method according to p. The method of claim 1, wherein a signal representing the required rolling pressure is provided to calculate a specific value of the control factor. 7. The method according to p. The method of claim 6, characterized in that the value of the rolling pressure is controlled and the pressure is adjusted to a value within the required range, if the value is outside the required range. 8. A device for bricking the welding temperature in a pipe mill with high frequency resistance welding, containing measuring devices for measuring the parameters of the welding process, characterized by the fact that it includes a counting system (54) for calculating the required speed of the rolling mill according to the equation S = - -, where S is required speed ATW of the mill bone, I is the heating current, W is the wall thickness, KR is the constant and T is the required temperature increase of the welded material , a signal source (56) connected to the calculator (54) to supply a signal (58) representing the actual wall thickness thereto, a converter (38) connected to the 17 110 411 1S calculator (54) for supplying a signal thereto (52) representing the actual heating current, a source (60) of the "signals" attached to the counting system (54) for supplying to it KR a signal representing -;, the elements attached to the rolling mill for the supply are A pin (94) representing the actual speed of the rolling mill, summing the operational amplifier (66) connected to the computing circuit (54) and to the signal supplying elements (94) for comparing the actual speed of the rolling mill with the required speed of the rolling mill, and the elements attached to the summing operational amplifier (66) and the mill drive motor (90), sensitively to compare the cited signals for changing the speed of the mill drive motor. 9. Device according to claim The method of claim 8, characterized in that the processing system (38) for supplying a signal (52) representing the actual heating current is provided with a set of conductive guides (22) connected to a high frequency power source (10) for supplying welding power, the sensor , the current (28) placed in the groove (24) on the surface (26) of the set of conductive guides (22) and having a ceramic core (30) on which the winding of a thin insulating wire (32) is wound, here Connected by a protective glass tube (34), the core (30) and the converter (38) being attached to the winding to provide a power signal according to the computing circuit (54). 10. Device according to claim The method of claim 8, characterized in that means for varying the speed of the motor driving the mill comprising means for limiting the change of speed to a predetermined value below and a specific value above the predetermined speed of the mill in response to said comparison. 11. Device according to claim According to claim 8, characterized in that it comprises pressure sensors for measuring the static pressure exerted by the rolling rolls (16), pressure sensors for measuring the dynamic pressure exerted by the roll and rolling (16), comparison elements attached to the pressure sensors for comparison static and dynamic pressures and elements attached to the comparing elements, to the circuit (38) for supplying the current signal and to the computing circuit (54), and the comparison sensitive for providing an adjustable current signal to the computing circuit (54). 12. A device for controlling the welding temperature in a tube mill with high frequency resistance welding, containing measuring devices for measuring the parameters of the welding process, characterized in that it includes a multiplier-divider (100) for calculating the required AT AT value according to the equation = KR Kr = -: the day AT is the actual increase WS of the temperature of the welded material, KR is constant, I is the heating current, W is the wall thickness and S is the actual speed of the rolling mill, the source (56) of signals connected to of the multiplier (100) for supplying it with a signal (58) representing the actual wall thickness, a processing circuit (38) attached to the multiplier (100) for providing it with a signal (52) representing the real wall heating current, elements attached to the multiplier-divider (100) and to the rolling mill to provide a signal (94) representing the actual speed of the rolling mill, the elements for supplying AT are the representative ygel, where KR is the constant KR and AT is the required temperature increment of the welded material, summing the operational amplifier (104) and the sampling and memory circuit (106) attached to the multiplier-decimal system (100) and of the AT signal supply elements representing, for comparing the KR AT signal representing the real signal with the Kr AT signal representing the required signal, and Kr elements attached to the comparing elements and to the high frequency power supply system (10) and sensitive to comparing these signals for change heating current. 13. Device according to claim 12. The apparatus of claim 12, characterized in that a processing circuit (38) for providing a signal (52) representing the actual heating current is provided with a set of conductive guides (22) connected to the high frequency power source (10) providing it welding power, a current sensor (28) placed in a groove (24) on the surface (26) of the conductive guide assembly (22) and having a ceramic core (30) on which a winding of a thin wire is wound insulation (32), surrounded by a protective glass tube (34), the core (30) and the converter (38) being attached to the winding to provide a current signal in accordance with the multiplier-divider (100) . 14. Device according to claim The method of claim 12, characterized in that the means for changing the heating current comprises means for limiting the change of the heating current to a predetermined value below and a certain value above a predetermined level of the heating current. 15. Device according to claim 12, characterized in that it comprises pressure sensors for measuring the static pressure exerted by the rolling rolls (16), pressure sensors for measuring the dynamic pressure exerted by the rolling rolls (16), comparing means connected to the static pressure sensors and dynamic and components connected to the comparator means for the current signal supply circuit (38) and the computing circuit (54) and comparatively sensitive for providing an adjustable current signal to the computing circuit. 10 15 20 25 30 35 40 45 50 55 60 110 411 FIG. 2110 411 FIG. 4 ± J1 "fS In FIG. 5. N & vr ^ - ^ r ^ I ^ m» 10 A ~ 1 ^ "-i, V // ^ Sj // # - sp», «# k * 0 0 -p_Jt PL

Claims (5)

Claims 45 1. A method of controlling the welding temperature in a high frequency resistance welding tube mill, which consists in continuously measuring the basic values during welding, characterized by selecting a control factor whose actual value is compared to with the value required to where w AT is the temperature increase of the welded material, KR is a constant, I is the heating current, W is the wall thickness of the pipe and S is the speed of the rolling mill, 60 control parameters I and S of the rolling mill are continuously measured, continuously provides a signal representing the wall thickness and continuously computes one value of the control factor based on the equation, knowing the measured value I, the wall thickness signal, and the value of the remaining factor in the equation continuously provide the differential signal by comparing this one control factor value with another control factor value control parameter, one of the rolling mill control parameters is selected and this rolling mill control parameter is continuously varied depending on a differential signal. 2. The method according to claim The method of claim 1, wherein S is used as the control factor and Kr is used as the remaining factor and its value. the required value of AT and S is used as the control parameter of the rolling mill. 3. The method according to p. I, characterized in that AT is used as the control factor - Kr and the remaining factor and its value is the actual value of S and I is used as the control parameter of the rolling mill. 4. The method according to p. The method of claim 1, characterized in that the static pressure exerted by the rolling rolls is measured, the dynamic pressure exerted by the rolling rolls is continuously measured and the heating current is continuously calculated and the heating current is adjusted to make a calculation based on pressure measurements. static and dynamic. 5. The method according to p. The method of claim 1, characterized in that when the rolling mill control parameter is changed, the differential signal is continuously converted into a control signal, oscillating around zero, for the change of the rolling mill control parameter, and the value of the control signal, which oscillates around zero, is continuously limited to a specified value. to a level above zero and to a specific level below zero. 6. The method according to p. The method of claim 1, wherein a signal representing the required rolling pressure is provided to calculate a specific value of the control factor. 7. The method according to p. The method of claim 6, characterized in that the value of the rolling pressure is controlled and the pressure is adjusted to a value within the required range, if the value is outside the required range. 8. A device for bricking the welding temperature in a pipe mill with high frequency resistance welding, containing measuring devices for measuring the parameters of the welding process, characterized by the fact that it includes a counting system (54) for calculating the required speed of the rolling mill according to the equation S = - -, where S is required speed ATW of the mill bone, I is the heating current, W is the wall thickness, KR is the constant and T is the required temperature increase of the welded material , a signal source (56) connected to the calculator (54) to supply a signal (58) representing the actual wall thickness thereto, a converter (38) connected to the 17 110 411 1S calculator (54) for supplying a signal thereto (52) representing the actual heating current, a source (60) of the "signals" attached to the counting system (54) for supplying to it KR a signal representing -;, the elements attached to the rolling mill for the supply are A pin (94) representing the actual speed of the rolling mill, summing the operational amplifier (66) connected to the computing circuit (54) and to the signal supplying elements (94) for comparing the actual speed of the rolling mill with the required speed of the rolling mill, and the elements attached to the summing operational amplifier (66) and the mill drive motor (90), sensitively to compare the cited signals for changing the speed of the mill drive motor. 9. Device according to claim The method of claim 8, characterized in that the processing system (38) for supplying a signal (52) representing the actual heating current is provided with a set of conductive guides (22) connected to a high frequency power source (10) for supplying welding power, the sensor , the current (28) placed in the groove (24) on the surface (26) of the set of conductive guides (22) and having a ceramic core (30) on which the winding of a thin insulating wire (32) is wound, here Connected by a protective glass tube (34), the core (30) and the converter (38) being attached to the winding to provide a power signal according to the computing circuit (54). 10. Device according to claim The method of claim 8, characterized in that means for varying the speed of the motor driving the mill comprising means for limiting the change of speed to a predetermined value below and a specific value above the predetermined speed of the mill in response to said comparison. 11. Device according to claim According to claim 8, characterized in that it comprises pressure sensors for measuring the static pressure exerted by the rolling rolls (16), pressure sensors for measuring the dynamic pressure exerted by the roll and rolling (16), comparison elements attached to the pressure sensors for comparison static and dynamic pressures and elements attached to the comparing elements, to the circuit (38) for supplying the current signal and to the computing circuit (54), and the comparison sensitive for providing an adjustable current signal to the computing circuit (54). 12. A device for controlling the welding temperature in a tube mill with high frequency resistance welding, containing measuring devices for measuring the parameters of the welding process, characterized in that it includes a multiplier-divider (100) for calculating the required AT AT value according to the equation = KR Kr = -: the day AT is the actual increase WS of the temperature of the welded material, KR is constant, I is the heating current, W is the wall thickness and S is the actual speed of the rolling mill, the source (56) of signals connected to of the multiplier (100) for supplying it with a signal (58) representing the actual wall thickness, a processing circuit (38) attached to the multiplier (100) for providing it with a signal (52) representing the real wall heating current, elements attached to the multiplier-divider (100) and to the rolling mill to provide a signal (94) representing the actual speed of the rolling mill, the elements for supplying AT are the representative ygel, where KR is the constant KR and AT is the required temperature increment of the welded material, summing the operational amplifier (104) and the sampling and memory circuit (106) attached to the multiplier-decimal system (100) and of the AT signal supply elements representing, for comparing the KR AT signal representing the real signal with the Kr AT signal representing the required signal, and Kr elements attached to the comparing elements and to the high frequency power supply system (10) and sensitive to comparing these signals for change heating current. 13. Device according to claim 12. The apparatus of claim 12, characterized in that a processing circuit (38) for providing a signal (52) representing the actual heating current is provided with a set of conductive guides (22) connected to the high frequency power source (10) providing it welding power, a current sensor (28) placed in a groove (24) on the surface (26) of the conductive guide assembly (22) and having a ceramic core (30) on which a winding of a thin wire is wound insulation (32), surrounded by a protective glass tube (34), the core (30) and the converter (38) being attached to the winding to provide a current signal in accordance with the multiplier-divider (100) . 14. Device according to claim The method of claim 12, characterized in that the means for changing the heating current comprises means for limiting the change of the heating current to a predetermined value below and a certain value above a predetermined level of the heating current. 15. Device according to claim 12, characterized in that it comprises pressure sensors for measuring the static pressure exerted by the rolling rolls (16), pressure sensors for measuring the dynamic pressure exerted by the rolling rolls (16), comparing means connected to the static pressure sensors and dynamic and components connected to the comparator means for the current signal supply circuit (38) and the computing circuit (54) and comparatively sensitive for providing an adjustable current signal to the computing circuit. 10 15 20 25 30 35 40 45 50 55 60 110 411 FIG. 2110 411 FIG. 4 J1 "fS in FIG. 5. n & vr ^ - ^ r ^ I ^ m »10 A ~ 1 ^" -i, V // ^ Sj // # - s p »,« # k * 0 0-p_Jt PL